Adam, if you are not getting really clean files, there must be a problem. Either sensor, or PP. Something is obviously not right
I have both the 90 Summicron AA and the Elmarit, both calibrated across the range. Both lenses are very easy to focus, and do nail the point of focus every time.
Before I had both lenses calibrated, when I would focus at about 2 to 3 metres, there was about 8 cms of back focus, which wide open, would cause softness when taking a shot of portrait. Distance it was fine again. This was confirmed by the lab, and was adjusted and both are very easy to focus now.
